Drum and drum head construction



Jan. 14, 1969 HlDx-:KAZU YoKol 3,421,400

DRUM AND DRUM HEAD CONSTRUCTION Filed Dec. 19, 1966 FiG. i

' HIDEKAZISVSSJCZR Q 32 28 BY M ATT'ORNEY United States Patent O 8 Claims This invention relates to drumhead and dnuim construction, and more particularly, to a drumhead for mounting in a supporting drum structure `for retaining Ia drumhead sheet securely thereon.

Previously mountings for drumhead sheets particularly those made of synthetic plastic material, have been found to be either ineffective for such fuse or are relatively expensive to manufacture. Drumhead sheets of synthetic plastic material, such as Mylar have been -developed with desirable physical properties such as high tensile strength that are particularly suitable for use as `drumhead sheets which are subjected to high loading pressures and impact stress when in a l-oaded condition. Synthetic plastic drumheads such as Mylar are particularly diflicult to anchor because of their smooth surface.

It is an object of this invention to provide a dru-mhead having clamping means for retaining the brim portion of a drumhead sheet that is relatively inexpensive to manufacture.

Another object of this invention is to provide such a drumhead that increases its clamping action upon the brim of the drumhead sheet as additional pressure is applied to the drumhead sheet.

A further object of this invention is to provide such a drumhead that cooperates with the dr-um mounting to securely retain the brim of the drumhead sheet.

Other objects and advantages will be readily .apparent from the following detailed description and the attached drawing wherein:

FIGURE l is a fragmentary cross-sectional view of the drumhead of this invention illustrating the drumhead in the process of formation.

FIGURE 2 is 'a view similar to FIGURE l with the clamping lmembers of the drumhead illustrated in a final folded position.

FIGURE 3 is a fragmentary cross-sectional View illustrating the mounting of the drumhead of FIGURE 2 in a drum structure.

It has now been found that the foregoing objects and other advantages can be provided in a drumhead for use with a supporting drum wherein the drumhead has a drum sheet of synthetic plastic material with a circular crown and a shoulder disposed about the circumferential edge of the crown that extends away from the plane of the crown. An integral brim of the drumhead sheet is disposed about the outer edge of the shoulder and folded to form two spaced layers. Clamping means are provided for securely engaging the brim portion of the 'drumhead sheet so that the `drumhead may be mounted for use on a supporting drum stnucture.

The clampingjmeans has an outer clamp with a U- shaped body portion folded about and engaging the outer surface of the spaced layers of the brim. The outer clamp has a flange engaging the shoulder of the drumhead sheet through which pressure is applied to the clamping means as the drumhead sheet is stressed. The lclamping means also has an annular inner clamp which cooperates with the outer clamp for retaining the brim of the drumhead between these two members. The inner clamp -has an engaging portion disposed snugly between the spaced layers for clamping the brim securely between the inner and outer clamps. The inner clamp has a flange lfor engaging an adjacent supporting surface on a drum so that the inner and outer clamp increase their engaging pressure 3,421,400 Patented Jan. 14, 1969 with the brim when a strain is put on the drumhead sheet during use.

The two spaced layers of the brim and the channel formed by the U-shaped body portion of the outer cla-mp may extend generally in the same plane as the crown. This configuration is relatively economical to manufacture and readily supportable by a drum structure, as the clamping means may be inexpensively formed by sandwiching the brim of the drumhead sheet between inner and outer clamps of sheet material such as sheet metal, and then folding these members at their midpoint. The engaging portion of the inner clamp may thus be formed of sheet lmaterial folded about itself having an outer surface engaging the inner surface of the two spaced layers of the brim.

The flanges of the inner and outer clamps desirably extend away from the plane of the spaced layers of the brim so that force applied to the -dr-umhead sheet is transmitted to the outer clamp through its flange which in turn tends to move the brim and inner clamp toward the shoulder of the drumhead sheet. However the flange of the inner clamp is restrained against movement because it is adapated to abut against an adjacent surface of a supporting drum. Consequently, pressure applied to the outer clamp through its flange increases the clamping action of the inner and outer clamps on the brim portion of the drumhead sheet.

The clamping means Imay also include a belt of relatively rigid synthetic plastic material surrounding and securely engaging the outer surface of the U-shaped body portion of the outer clamp. This belt provides a convenient supporting surface for mounting the drumhead in a drum structure.

This invention includes a drum providing a support member engaging the drumhead sheet generally in the area of the junction of the crown and the shoulders. The -drum is attached so that the flange of the inner annular clamp engages a supporting surface of the drum so that the inner and outer clamps tighten their engagement with the Idrum when a strain is put on the drumhead sheet during use. The drum also has a clamping ring mounted in a conventional manner for engaging the belt of the drumhead for :stressing the drumhead sheet against the support member of the drum. The drum support member may be adapted so that is provides a supporting surface for the flange of the inner clamp. Specifically the supporting member may be tapered generally from the point of engagement with the flange of the inner clamp to a point adjacent the engagement of the support member with the drumhead sheet.

Referring now to the drawings, there is illustrated a drumhead, generally designated by the numeral 10, having an integrally formed drumhead sheet wtih a generally at circular crown 12 having a shoulder 14 about the circumferential periphery thereof extending downwardly away from the plane of the crown. A brim 16 extends from the lower circumferential edges of the shoulder 14 and outwardly generally parallel to the crown and folded downwardly and backwardly upon itself as to provide two spaced layers.

The brim 16 is securely anchored by clamping means having an outer annular cla-mp 18 with a U-shaped body portion folded 180 about the outer surface of the folded brim 16. The outer clamp has a flange 20 which extends upwardly therefrom and engages the shoulder 14 of the drumhead sheet. The clamping means also includes an inner annular clamp 22 having a U-shaped body portion folded into two layers upon itself and disposed fsnuggly between the spaced layers of the folded brim 16. The inner clamp 22 has a flange portion 24 extending downwardly away from the crown 12 of the drumhead sheet.

As illustrated in FIGURE 3,' the clamping means also may include a belt 25 of relatively rigid material which may be of synthetic plastic which surrounds and engages the outer surface of the U-shaped body portion of the outer clamp.

As illustrated in FIGURES 1 and 2, the drumhead 10 may be relatively economically and simply manufactured by providing the inner and outer clamp 18 and 22 of sheet material having the brim portion disposed herebetween. The inner andv outer clamps 18 and 22 may be then -folded downwardly 180 from the position illustrated in FIGURE l to the position illustrated in FIGURE 2 to provide an effective anchor for the drumhead sheet.

As illustrated in FIGURE 3 this invention includes a drum, fragmentarily shown and generally designated by the numeral 26, having an upwardly extending supporting member 28 which engages the drumhead sheet generally in the area between the crown 12 'and the shoulder 14. The supporting member 28 has a tapered portion 30 which extends downwardly and outwardly from its upper and to a point just before the contact of the flange 24 of the inner clamp 22 with the side tof the drum 32. The drum 26 has a tensioning ring 34 which is mounted thereon in a conventional manner and engages the upper surface of the belt 25. The tensioning ring 34 is adapted to apply pressure on the belt 25 so that the clamp means applies stress to the drumhead sheet.

In operation when tensioning pressure is applied to the drumhead sheet by the tensioning ring 34, and when other stresses are applied to the crown 12 of the drumhead sheet during use, the shoulder 14 in engagement with the flange 20 of the outer clamp 18 will have a tendency to pull the clamp means in the direction of the shoulder 14. As this occurs the flange 24 of the inner clamp presses against the side of the drum 32 which causes the inner and outer clamps 18 and 22 to increase their holding action on the brim 16 of the drumhead sheet. Accordingly, this invention provides an anchor for a drumhead sheet which increases its holding force on the brim 16 of the drum head as added stresses is applied thereof. Thus,` a drumhead construction is provided that effectively anchors a brim of relatively smooth synthetic plastic material in an effective manner.

This invention provides a drumhead having clamping means for retaining the brim portion of a drumhead which is relatively inexpensive to manufacture. The drumhead provides an anchor that increases its clamping action upon the brim of the drumhead as additional pressure is applied thereto. This invention also includes a drumhead construction which cooperates to Isecurely anchor the brim of a drumhead sheet.

It will be understood that the foregoing description with the details of exemplary structure is not to be construed in any way to limit the invention, but that modificaions may be made thereto without departing from the scope of the invention as set forth in the following claims.

Having thus described the invention, I claim:

1. A drumhead for mounting on a supporting drum comprising a drumhead sheet of synthetic plastic material having a generally ilat circular crown, .a shoulder disposed about the circumferential edge of said crown and extending away from the plane of said crown, and a brim about the outer edge of said shoulder folded to form two spaced layers; and clamping means having an annular outer clamp with a U-shaped body portion folded about and engaging the outer surface of said spaced layers of said brim, said outer clamp having a flange engaging the shoulder of the drumhead sheet; said clamping means Valso having a cooperating annular inner clamp with an engaging portion disposed snugly between said spaced layers for clamping said brim securely between said inner and outer clamps, said inner clamp having a flange for engaging the supporting drum so that said inner and outer clamps tighten their engagement with said brim when a strain is put on said drumhead sheet during use.

2. The drumhead of claim 1 wherein said two spaced layers of said brim and the channel formed by said U- shaped body portion of said outer clamp extend generally parallel to said crown.

3. The drumhead -of claim 1 wherein said flanges on said inner and outer clamps extend away from the plane of said spaced layers of said brim.

4. The drumhead of claim 1 wherein said engaging portion of said inner clamp is sheet material folded over on itself having an outer surface engaging the inner surface of said two spaced layers of said brim.

5. The drumhead of claim 1 wherein said clamping means includes a belt of relatively rigid synthetic plastic material surrounding and securely engaging the outer surface of said U-shaped body portion of said outer clamp for supporting said drumhead in a drum.

6. A drum and drumhead comprising ya drumhead sheet of synthetic plastic material having a generally ilat circular crown, a shoulder disposed about the circumferential edge of said crown and extending away from the plane of said crown, and a brim about the outer edge of said shoulder folded to form two spaced layers; a drum having a support member engaging said drumhead generally in the area of the junction of said crown and shoulder; and clamping means having an annular outer clamp with a U-shaped body portion folded about and engaging the outer surface of said spaced layers of said brim, said outer clamp having a flange engaging the shoulder of the drumhead sheet; said clamping means also having a cooperation annular inner clamp with an engaging portion disposed snugly between said spaced layers for clamping said brim securely 'between said inner and outer clamps, said inner clamp having ya flange engaging a supporting surface of said drum so that said inner and louter clamps tighten their engagement with said brim when a strain is put on said drumhead sheet during use; said clamping means including a belt yof relatively stiff material surrounding and engaging the outer surface of said U-shaped body portion of said outer clamp; and said drum having a clamping ring engaging said belt for stressing said drumhead sheet against said support member.

7. The drum 'and drumhead of claim 6 wherein said support member of said drum is configured to engage said flange of said inner clamp.

8. The dr-um and ldrumhead of claim 7 wherein said support member is tapered generally from the point of engagement with the flange of said inner clamp to a point generally adjacent the engagement of said support member with said drumhead sheet.

References Cited UNITED STATES PATENTS 772,743 lO/ 1904 Oschatz 84-411 2,009,060 7/1935 Hiers et al. 84--411 2,979,981 4/1961 Ludwig 84-411 RICHARD B. WILKINSON, Primary Examiner.

L. R. FRANKLIN, Assistant Examiner'. 

1. A DRUMHEAD FOR MOUNTING ON A SUPPORTING DRUM COMPRISING A DRUMHEAD SHEET OF SYNTHETIC PLASTIC MATERIAL HAVING A GENERALLY FLAT CIRCULAR CROWN, A SHOULDER DISPOSED ABOUT THE CIRCUMFERENTIAL EDGE OF SAID CROWN AND EXTENDING AWAY FROM THE PLANE OF SAID CROWN, AND A BRIM ABOUT THE OUTER EDGE OF SAID SHOULDER FOLDED TO FORM TWO SPACED LAYERS; AND CLAMPING MEANS HAVING AN ANNULAR OUTER CLAMP WITH A U-SHAPED BODY PORTION FOLDED ABOUT AND ENGAGING THE OUTER SURFACE OF SAID SPACED LAYERS OF SAID BRIM, SAID OUTER CLAMP HAVING A FLANGE ENGAGING THE SHOULDER OF THE DRUMHEAD SHEET; SAID CLAMPING MEANS 